1. Field of the Invention
This invention relates to a method for the manufacture of aluminum sulfate and, in particular, to a continuous process for the manufacture of aluminum sulfate from alumina-containing solids and sulfuric acid.
2. Description of the Prior Art
The production of aluminum sulfate from alumina-containing solids by reaction with sulfuric acid has been characterized by discontinuous, batch processing involving long residence times in autoclaves, reaction vessels and the like. Normally, the reaction has been conducted at atmospheric pressures, however, a batch process performed at superatmospheric pressures is disclosed in U.S. Pat. No. 1,679,366. Some attempts at continuous processing have involved relatively complex processing schemes employing multiple reaction zones or stages such as disclosed in U.S. Pat. Nos. 3,079,228; 3,143,392; 2,273,930; 3,185,545; or 3,216,792. In most of these processes there are incremental additions of sulfuric acid and/or alumina during the staged processing to achieve substantially complete reaction and to provide a close control over the sulfuric acid to alumina ratios. All of these reactions, however, have required relatively lengthy reaction periods and extensive processing equipment.